Method of riveting



April 12, 1949- l.. c. HucK 2,466,811

METHOD oF nIvETING April 12,` 1949. L. c. l-lucKl 2,466,811

METHOD OF RIVETING Filed April so, 1945 2 sheetssheet 2 Patented Apr.12, 1949 METHOD F RIVETING Louis C. Huck, Grosse Pointe, Mich.,assigner, by mesne assignments, to Huck Manufacturing Company, Detroit,Mich., a corporation of Michigan Application April 30, 1945, Serial No.591,052

The invention relates to riveting mechanisms,

and it has particular relation to a method of setting a two-part rivet.

In setting a blind rivet, as for instance the -brazier head typedisclosed in my copending apfactors which tend to extrude the tubularmember axially ahead of the shoulder particularly if more metal is aheadof the shoulder than that needed to fill the opening or hole. Thisextrusion when it occurs may cause an extrusion rise of the brazier headso as to leave a space between the head and structure, or if the platenext to the head moves with the extrusion and hence, moves with thehead, the plates may separate to some extent.

After the movement of the shoulder to ll the opening or hole, a head onthe pin moves against y the end of the tubular member opposite thebrazier head and forms the blind head. Thereafter increased pull on thepin causes a secondary anvil to force a locking collar on the brazierhead into a recess in the latter and a recess in the pin, so as to lockthe pin and tubular member together. Then continued increase in pull onthe pin causes it to break under tension.

Another object of the invention is to provide a method of riveting whichwill effect return of the radially outer part of the head on the tubularmember in the event of an extrusion rise thereof as mentioned.

Other objects of the invention will become apparent from the followingspecification, from the drawings relating thereto, and from the claimshereinafter set forth.

For a better understanding of the invention reference may be had to thedrawings wherein:

Figure 1 is a cross-sectional view illustrating a rivet in its unsetcondition association with a riveting mechanism constructed according toone form of the invention; and,

Figs. 2, 3, and 4 are similar v iews showing the v rivet in intermediatestages of the riveting oper- 'Il' having openings I2 and I3 forreceiving the rivet. The rivet comprises a tubular 'member extendingthrough the openings I2 and I3 and having a preformed or manufacturedhead I5 engaging the outer side of plate I I, and the underside of thishead has a recess I6 adapted to allow for any burrs around the plateopening. Within the openings I2 and I3, the tubular body is of smallerinternal diameter as indicated at I'I and at the outer side of plateIII, a projecting portion I8 of larger internal diameter is provided.The junction of the two portions I1 and I8 is formed with an annular,conical shoulder I9.

The head I5 shown is of the brazier type and is provided with a central,conical recess 20 which joins a smaller counterbore or recess 2l at itsinner end. An annular locking collar 22 axially aligned with the Irecess20 is initially joined to the head I5 by means of a web 23, and thiscollar before the rivet is set, projectsaxially outwardly from thesurface of the head.

The second part of the rivet comprises a pin having a conical shoulder25 which engages the shoulder I9 in the tubular member, and when the pinis pulled through the tubular body, the shoulder 25 causes radialexpansion of the portion II of the body so as to iill the openings I2and I3. It might be noted that the largest diameter of the shoulder 25is approximately equal to or slightly less than the diameter ofcounterbcre 2l, and also that it is less than the inside diameter of thebody portion I8 so that a portion of the shoulder I9 remains after theshoulder 25 has been pulled through the body. The pin also includes anannular relatively deep breakneck or groove 21 which is the weakest partof the pin and a second groove 28 of slightly larger diameter which isadapted to receive the collar 22 in a later part of the rivetingoperation.

A head 29 on the end of the pin is adapted to engage and move the end ofthe body portion I8.

so as tocause the latter to bulb outwardly and form what is known as theblind head. It might be mentioned here'that the outer end of the bodyportion I8 is inherently stronger so as to cause it to remain inunexpanded condition and thereby assure bulbing of the portion I8between the plate III and such strengthened end, and the manner in whichthe end of the body portion I8 is strengthened is more particularly. setforth in the copending application for patent previously identiiied. Thepin also includes a shoulder SII which is adapted to engage thatremaining part of shoulder I9 in the iinal stage of forming the blind orbulbed head from the body portion I8 so as to cooperate in limitingfurther movement of the pin through the body.v

The rivet is adapted to be set by a rivet setting mechanism whichincludes aprimary anvil 32 having a concave surface 33 for engaging theradially outer portion of the brazier head I5, but towards its centerthe anvil is relieved by a reversely curved face 34 and a counterboreformed by an axial-wa ll 35 and a radial wall 3B. The purpose offthisrelief in -the anvil and the wall or bottom 3i of the counterbore willbe presently considered.

The secondary anvil is indicated at 31 andis adapted to force the collar22 into the recess 20 in a later part of the riveting operation. Theriveting mechanism also includes jaws 38 shown by Fig. 4 for grippingthe outer grooved end of the pin indicated at 33 and pulling it in thedirecl, heador with a less ductile metal in the head, the

tion of the arrow as shown on the-pin, and the reaction to this pull isapplied successively to the anvils 32 and 31 in the opposite ldirection,as also shown by arrows. Details of a gun or riveting mechanismhavingtwo anvils are mentioned infthefcopending application for patent.

In setting the rivet the pin is gripped and pulled in the direction ofthe arrow on the pin, and this causes the shoulder. 25 initially toexpand the body portion I1 so as to ll the openings in the; structure,and while this is occurring, the reaction'force is applied `by the anvil32 to the head I5. `iis the shoulder 25 advances through the thickerwall portion I1 of the tubular body, it forces the metal outwardly tofill the openings, and it is desirable that there be sumcient metal tofill the openings. In order to assure obtaining this result even thoughinitial hole clearance around the rivet may vary. the wall portion I1 ismade thick enough to provide s'uiiicient hole filling metal for thelarger'clearances which may occur in the usual range ofpvariations inhole clearance. It follows from this that there may usually be a surplusof metal over and above thatv required to fill the hole. Hence, it willbe found where there is surplus metal that the shoulder 25 inmoving'through .the tubular body portion I1 actually will cause the bodyportion ahead o f the shoulder to flow, and this will cause 'a rise ofheadl I5 in the same direction as the shoulder is moving so as to moveit slightly away from the plate II as shown in Fig. 2.. This extrusionrise of head I5 will occur even though the anvil 32 is applying thereaction force to the head. In other words as' the conical shoulderexpands the hole filling portion of the body, the holel ls rst filled,-and then 4during further movement of the shoulder its tapered or conicalsurface will apply powerful expanding forces to the inside wall of thebody due to the -powerful force effective through the taperedengagement. With the hole filled this forceacts with suiiicient power tokelongate thebody ahead of the shoulder and to cause the head I5. torise above the plate II and to move the-anvil with it. The shoulder25may finally carry a small amount of metal with it into the counterbore2l but such metal will be ironed out against the wall of thecounterbore. Thus, the counterbore provides a space for such metal andprevents. its movement into the locking recess 20.

The present invention is' particularly concerned with returning orbending the radially outer part of the head I5 into contact `with theplate II after such elongation rise, and also bringing theplatestogetherif they have been separated by the elongation` However, -due to the factthe blind head yet must be formed, it is necessary that the. tubularbodybe held against movement in the openings in the platesias the yh easi 23.on

metal and dimensions in the shank remaining the same the counterbore orwall 3l in the anvil must be increased in diameter to provide a greatermoment arm, and with a thinner head or more ductile metal'in the head,the counterbore and wall 36,. must be reduced in diameter. From anotherpoint of view, the engagement between the anvil and head must be sorelated to the thickness of head and deformability of the metal of thehead relative to the collapsabiiity of the shank as to prevent bendingof the radially outer part of the head towards' the plate II prior toformation of the blind head because if the head bends before the blindhead is formed',` its pushing against .the plate 'might push them alongthe shank toward the head 28 and, of course, preventionl of suchmovement relative to the body is important.

With the anvil 32 now holding the head I5 as 4seen in4 Fig. 2, the head25 on the pin moves I9 on the tubular member andv this engagement theanvil 32 is provided so as to limit or stopin commotion with theengagement between the head 23 on the pin and the blind head effectivelystops. further movement of the pin, at least to any appreciable extent.lWith this increase in resistance toppln movement, the pull on the pinincreases4 and consequently the reaction vagainst anvil 32 increases. Itfollows that more and more pressure is applied against the radiallyouter portion of head I5 and until the anvil bends or moves the radiallyouter part of the head towards the structure as seen in Fig. 4. Thisbrings the plates together and also closes any gap between the head andplate II except for lthe recess I6 which, remains and which in fact isslightly deeper due to the extrusion rise of head I5.

Following this bending or movement of the radially outer part of headI5, further increase in pull on the pin, and the reaction appliedagainst head I5 by anvil 32 will automatically cause the reaction to thepull on the pin to shift to the secondary anvil 31, and this anvil thenforces the collar 22 into the recess 20 in head I5. At the time thecollar is thus forced into the recess 20, the groove 28 is radiallyaligned with recess 2B and. the collar is forced into the locking groovealso, and thus. the pin and tubular member are locked together withinthe head I5. After this lock is obtained tension on the pin will furtherincrease until it is suiiicient to break the pin-at the breakneck 21. Itmay be noted here that the pin pulling forces progressively increasethrough the hole filling, blind head forming, head bend-` ing. collarlocking and pin breaking operations.

The wall or bottom 38 in the counterbore in any extrusion of the innerpart of the head I5 ,into the counterbore in the event .such movementshould occur under certain circumstances. For. example, in viewofmanufacturing tolerances and variations in theA metal or othervariables, the condition may at some time occur where the head I afterthe hole filling operation would bend over against the plate II, beforethe blind head forms In that case. the tubular body might be pulled withthe 'pin by the engagement of the head 30 on the pin with the end of thetubular member but if this occurs the wall 36 of the counterbore wouldpositively limit the movement. This insures that the projecting portionI8 of the body will not be appreciably shortened and that continued pullon the pin will form a blind head Particularly where the thickness ofthe plates approaches the maximum of the range of thickness for anygiven length of tubular memberv it is important that the projecting bodyportion I8 not be shortened appreciably since suflicient length ofprojection must be maintained in order to form a satisfactory blindhead.

Normally therefore. where there is surplus metal ahead of the holefilling shoulder 25, an extrusion rise of head I5 may occur and the headwill carry the anvil with it due to the extrusion forces. Then when thehead 30 on the pin begins to move the end of body portion I8, therelation between the anvil and head I5 is such as to prevent movement ofthe tubular member throughl thc structure, and the head is not bent bythe anvil until the blind head is formed. Normally then. it is onlyafter the blind head forming operation that the forces applied by theanvil be- What is claimed is:

The method of setting a rivet of a type including a tubular memberhaving a centrally opened preformed head at one end, an intermediatebody portion and an opposite end portion of larger inside diameter thanthe inside diameter of said intermediate portion anda pin extendingthrough the tubular member and having a shoulder engaging theintermediate body and having means on one end initially spaced from butdesigned for engaging said end portion of the tubular member, whichcomprises inserting the assembled rivet and pin into openings in astructure to be riveted with the intermediate portion in said openings,with the preformed head abutting one face of the structure and with saidopposite end portion protruding beyond the structure, pulling the pinand applying the reaction force to the preformed head so as to form ablind head on the opposite end of the rivet, and then applying asubstantially entirely axially directed force to an annular areaextending radially outwardly from substantially the mid point betweenthe outer surface of the stem and the outer annular edge of the -head toforce the radially outer portion only of the head towards and againstthe structure.

LOUIS C. HUCK.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Name Date Huck Sept. 8, 1936 Huck Nov. 24, 1936Huck --a Apr. 19, 1938 Lees Mar; 13,1945 Fischer Mar. 5, 1946 Huck Mar.26, 1946 FOREIGN PATENTS Country Date France June 7, 1937 .Number Number

